Commit b3b0d09c authored by Eric B Munson's avatar Eric B Munson Committed by Linus Torvalds

selftests: vm: add tests for lock on fault

Test the mmap() flag, and the mlockall() flag.  These tests ensure that
pages are not faulted in until they are accessed, that the pages are
unevictable once faulted in, and that VMA splitting and merging works with
the new VM flag.  The second test ensures that mlock limits are respected.
 Note that the limit test needs to be run a normal user.

Also add tests to use the new mlock2 family of system calls.

[treding@nvidia.com: : Fix mlock2-tests for 32-bit architectures]
[treding@nvidia.com: ensure the mlock2 syscall number can be found]
[treding@nvidia.com: use the right arguments for main()]
Signed-off-by: default avatarEric B Munson <emunson@akamai.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b0f205c2
......@@ -5,6 +5,8 @@ BINARIES = compaction_test
BINARIES += hugepage-mmap
BINARIES += hugepage-shm
BINARIES += map_hugetlb
BINARIES += mlock2-tests
BINARIES += on-fault-limit
BINARIES += thuge-gen
BINARIES += transhuge-stress
BINARIES += userfaultfd
......
#include <sys/mman.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <syscall.h>
#include <errno.h>
#include <stdbool.h>
#ifndef MLOCK_ONFAULT
#define MLOCK_ONFAULT 1
#endif
#ifndef MCL_ONFAULT
#define MCL_ONFAULT (MCL_FUTURE << 1)
#endif
static int mlock2_(void *start, size_t len, int flags)
{
#ifdef __NR_mlock2
return syscall(__NR_mlock2, start, len, flags);
#else
errno = ENOSYS;
return -1;
#endif
}
struct vm_boundaries {
unsigned long start;
unsigned long end;
};
static int get_vm_area(unsigned long addr, struct vm_boundaries *area)
{
FILE *file;
int ret = 1;
char line[1024] = {0};
char *end_addr;
char *stop;
unsigned long start;
unsigned long end;
if (!area)
return ret;
file = fopen("/proc/self/maps", "r");
if (!file) {
perror("fopen");
return ret;
}
memset(area, 0, sizeof(struct vm_boundaries));
while(fgets(line, 1024, file)) {
end_addr = strchr(line, '-');
if (!end_addr) {
printf("cannot parse /proc/self/maps\n");
goto out;
}
*end_addr = '\0';
end_addr++;
stop = strchr(end_addr, ' ');
if (!stop) {
printf("cannot parse /proc/self/maps\n");
goto out;
}
stop = '\0';
sscanf(line, "%lx", &start);
sscanf(end_addr, "%lx", &end);
if (start <= addr && end > addr) {
area->start = start;
area->end = end;
ret = 0;
goto out;
}
}
out:
fclose(file);
return ret;
}
static uint64_t get_pageflags(unsigned long addr)
{
FILE *file;
uint64_t pfn;
unsigned long offset;
file = fopen("/proc/self/pagemap", "r");
if (!file) {
perror("fopen pagemap");
_exit(1);
}
offset = addr / getpagesize() * sizeof(pfn);
if (fseek(file, offset, SEEK_SET)) {
perror("fseek pagemap");
_exit(1);
}
if (fread(&pfn, sizeof(pfn), 1, file) != 1) {
perror("fread pagemap");
_exit(1);
}
fclose(file);
return pfn;
}
static uint64_t get_kpageflags(unsigned long pfn)
{
uint64_t flags;
FILE *file;
file = fopen("/proc/kpageflags", "r");
if (!file) {
perror("fopen kpageflags");
_exit(1);
}
if (fseek(file, pfn * sizeof(flags), SEEK_SET)) {
perror("fseek kpageflags");
_exit(1);
}
if (fread(&flags, sizeof(flags), 1, file) != 1) {
perror("fread kpageflags");
_exit(1);
}
fclose(file);
return flags;
}
static FILE *seek_to_smaps_entry(unsigned long addr)
{
FILE *file;
char *line = NULL;
size_t size = 0;
unsigned long start, end;
char perms[5];
unsigned long offset;
char dev[32];
unsigned long inode;
char path[BUFSIZ];
file = fopen("/proc/self/smaps", "r");
if (!file) {
perror("fopen smaps");
_exit(1);
}
while (getline(&line, &size, file) > 0) {
if (sscanf(line, "%lx-%lx %s %lx %s %lu %s\n",
&start, &end, perms, &offset, dev, &inode, path) < 6)
goto next;
if (start <= addr && addr < end)
goto out;
next:
free(line);
line = NULL;
size = 0;
}
fclose(file);
file = NULL;
out:
free(line);
return file;
}
#define VMFLAGS "VmFlags:"
static bool is_vmflag_set(unsigned long addr, const char *vmflag)
{
char *line = NULL;
char *flags;
size_t size = 0;
bool ret = false;
FILE *smaps;
smaps = seek_to_smaps_entry(addr);
if (!smaps) {
printf("Unable to parse /proc/self/smaps\n");
goto out;
}
while (getline(&line, &size, smaps) > 0) {
if (!strstr(line, VMFLAGS)) {
free(line);
line = NULL;
size = 0;
continue;
}
flags = line + strlen(VMFLAGS);
ret = (strstr(flags, vmflag) != NULL);
goto out;
}
out:
free(line);
fclose(smaps);
return ret;
}
#define SIZE "Size:"
#define RSS "Rss:"
#define LOCKED "lo"
static bool is_vma_lock_on_fault(unsigned long addr)
{
bool ret = false;
bool locked;
FILE *smaps = NULL;
unsigned long vma_size, vma_rss;
char *line = NULL;
char *value;
size_t size = 0;
locked = is_vmflag_set(addr, LOCKED);
if (!locked)
goto out;
smaps = seek_to_smaps_entry(addr);
if (!smaps) {
printf("Unable to parse /proc/self/smaps\n");
goto out;
}
while (getline(&line, &size, smaps) > 0) {
if (!strstr(line, SIZE)) {
free(line);
line = NULL;
size = 0;
continue;
}
value = line + strlen(SIZE);
if (sscanf(value, "%lu kB", &vma_size) < 1) {
printf("Unable to parse smaps entry for Size\n");
goto out;
}
break;
}
while (getline(&line, &size, smaps) > 0) {
if (!strstr(line, RSS)) {
free(line);
line = NULL;
size = 0;
continue;
}
value = line + strlen(RSS);
if (sscanf(value, "%lu kB", &vma_rss) < 1) {
printf("Unable to parse smaps entry for Rss\n");
goto out;
}
break;
}
ret = locked && (vma_rss < vma_size);
out:
free(line);
if (smaps)
fclose(smaps);
return ret;
}
#define PRESENT_BIT 0x8000000000000000
#define PFN_MASK 0x007FFFFFFFFFFFFF
#define UNEVICTABLE_BIT (1UL << 18)
static int lock_check(char *map)
{
unsigned long page_size = getpagesize();
uint64_t page1_flags, page2_flags;
page1_flags = get_pageflags((unsigned long)map);
page2_flags = get_pageflags((unsigned long)map + page_size);
/* Both pages should be present */
if (((page1_flags & PRESENT_BIT) == 0) ||
((page2_flags & PRESENT_BIT) == 0)) {
printf("Failed to make both pages present\n");
return 1;
}
page1_flags = get_kpageflags(page1_flags & PFN_MASK);
page2_flags = get_kpageflags(page2_flags & PFN_MASK);
/* Both pages should be unevictable */
if (((page1_flags & UNEVICTABLE_BIT) == 0) ||
((page2_flags & UNEVICTABLE_BIT) == 0)) {
printf("Failed to make both pages unevictable\n");
return 1;
}
if (!is_vmflag_set((unsigned long)map, LOCKED)) {
printf("VMA flag %s is missing on page 1\n", LOCKED);
return 1;
}
if (!is_vmflag_set((unsigned long)map + page_size, LOCKED)) {
printf("VMA flag %s is missing on page 2\n", LOCKED);
return 1;
}
return 0;
}
static int unlock_lock_check(char *map)
{
unsigned long page_size = getpagesize();
uint64_t page1_flags, page2_flags;
page1_flags = get_pageflags((unsigned long)map);
page2_flags = get_pageflags((unsigned long)map + page_size);
page1_flags = get_kpageflags(page1_flags & PFN_MASK);
page2_flags = get_kpageflags(page2_flags & PFN_MASK);
if ((page1_flags & UNEVICTABLE_BIT) || (page2_flags & UNEVICTABLE_BIT)) {
printf("A page is still marked unevictable after unlock\n");
return 1;
}
if (is_vmflag_set((unsigned long)map, LOCKED)) {
printf("VMA flag %s is present on page 1 after unlock\n", LOCKED);
return 1;
}
if (is_vmflag_set((unsigned long)map + page_size, LOCKED)) {
printf("VMA flag %s is present on page 2 after unlock\n", LOCKED);
return 1;
}
return 0;
}
static int test_mlock_lock()
{
char *map;
int ret = 1;
unsigned long page_size = getpagesize();
map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
if (map == MAP_FAILED) {
perror("test_mlock_locked mmap");
goto out;
}
if (mlock2_(map, 2 * page_size, 0)) {
if (errno == ENOSYS) {
printf("Cannot call new mlock family, skipping test\n");
_exit(0);
}
perror("mlock2(0)");
goto unmap;
}
if (lock_check(map))
goto unmap;
/* Now unlock and recheck attributes */
if (munlock(map, 2 * page_size)) {
perror("munlock()");
goto unmap;
}
ret = unlock_lock_check(map);
unmap:
munmap(map, 2 * page_size);
out:
return ret;
}
static int onfault_check(char *map)
{
unsigned long page_size = getpagesize();
uint64_t page1_flags, page2_flags;
page1_flags = get_pageflags((unsigned long)map);
page2_flags = get_pageflags((unsigned long)map + page_size);
/* Neither page should be present */
if ((page1_flags & PRESENT_BIT) || (page2_flags & PRESENT_BIT)) {
printf("Pages were made present by MLOCK_ONFAULT\n");
return 1;
}
*map = 'a';
page1_flags = get_pageflags((unsigned long)map);
page2_flags = get_pageflags((unsigned long)map + page_size);
/* Only page 1 should be present */
if ((page1_flags & PRESENT_BIT) == 0) {
printf("Page 1 is not present after fault\n");
return 1;
} else if (page2_flags & PRESENT_BIT) {
printf("Page 2 was made present\n");
return 1;
}
page1_flags = get_kpageflags(page1_flags & PFN_MASK);
/* Page 1 should be unevictable */
if ((page1_flags & UNEVICTABLE_BIT) == 0) {
printf("Failed to make faulted page unevictable\n");
return 1;
}
if (!is_vma_lock_on_fault((unsigned long)map)) {
printf("VMA is not marked for lock on fault\n");
return 1;
}
if (!is_vma_lock_on_fault((unsigned long)map + page_size)) {
printf("VMA is not marked for lock on fault\n");
return 1;
}
return 0;
}
static int unlock_onfault_check(char *map)
{
unsigned long page_size = getpagesize();
uint64_t page1_flags;
page1_flags = get_pageflags((unsigned long)map);
page1_flags = get_kpageflags(page1_flags & PFN_MASK);
if (page1_flags & UNEVICTABLE_BIT) {
printf("Page 1 is still marked unevictable after unlock\n");
return 1;
}
if (is_vma_lock_on_fault((unsigned long)map) ||
is_vma_lock_on_fault((unsigned long)map + page_size)) {
printf("VMA is still lock on fault after unlock\n");
return 1;
}
return 0;
}
static int test_mlock_onfault()
{
char *map;
int ret = 1;
unsigned long page_size = getpagesize();
map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
if (map == MAP_FAILED) {
perror("test_mlock_locked mmap");
goto out;
}
if (mlock2_(map, 2 * page_size, MLOCK_ONFAULT)) {
if (errno == ENOSYS) {
printf("Cannot call new mlock family, skipping test\n");
_exit(0);
}
perror("mlock2(MLOCK_ONFAULT)");
goto unmap;
}
if (onfault_check(map))
goto unmap;
/* Now unlock and recheck attributes */
if (munlock(map, 2 * page_size)) {
if (errno == ENOSYS) {
printf("Cannot call new mlock family, skipping test\n");
_exit(0);
}
perror("munlock()");
goto unmap;
}
ret = unlock_onfault_check(map);
unmap:
munmap(map, 2 * page_size);
out:
return ret;
}
static int test_lock_onfault_of_present()
{
char *map;
int ret = 1;
unsigned long page_size = getpagesize();
uint64_t page1_flags, page2_flags;
map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
if (map == MAP_FAILED) {
perror("test_mlock_locked mmap");
goto out;
}
*map = 'a';
if (mlock2_(map, 2 * page_size, MLOCK_ONFAULT)) {
if (errno == ENOSYS) {
printf("Cannot call new mlock family, skipping test\n");
_exit(0);
}
perror("mlock2(MLOCK_ONFAULT)");
goto unmap;
}
page1_flags = get_pageflags((unsigned long)map);
page2_flags = get_pageflags((unsigned long)map + page_size);
page1_flags = get_kpageflags(page1_flags & PFN_MASK);
page2_flags = get_kpageflags(page2_flags & PFN_MASK);
/* Page 1 should be unevictable */
if ((page1_flags & UNEVICTABLE_BIT) == 0) {
printf("Failed to make present page unevictable\n");
goto unmap;
}
if (!is_vma_lock_on_fault((unsigned long)map) ||
!is_vma_lock_on_fault((unsigned long)map + page_size)) {
printf("VMA with present pages is not marked lock on fault\n");
goto unmap;
}
ret = 0;
unmap:
munmap(map, 2 * page_size);
out:
return ret;
}
static int test_munlockall()
{
char *map;
int ret = 1;
unsigned long page_size = getpagesize();
map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
if (map == MAP_FAILED) {
perror("test_munlockall mmap");
goto out;
}
if (mlockall(MCL_CURRENT)) {
perror("mlockall(MCL_CURRENT)");
goto out;
}
if (lock_check(map))
goto unmap;
if (munlockall()) {
perror("munlockall()");
goto unmap;
}
if (unlock_lock_check(map))
goto unmap;
munmap(map, 2 * page_size);
map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
if (map == MAP_FAILED) {
perror("test_munlockall second mmap");
goto out;
}
if (mlockall(MCL_CURRENT | MCL_ONFAULT)) {
perror("mlockall(MCL_CURRENT | MCL_ONFAULT)");
goto unmap;
}
if (onfault_check(map))
goto unmap;
if (munlockall()) {
perror("munlockall()");
goto unmap;
}
if (unlock_onfault_check(map))
goto unmap;